Video apparatus with reduced artifact and memory storage for improved motion estimation

ABSTRACT

At least a computer program product comprising computing instructions stored on a non-transitory computer storage medium is provided. The computer program product is provided for efficiently encoding or decoding a video frame to smooth out or reduce visual distortions such as visual artifact between different video subsections encoded with different compression methods within a video frame. In addition, an improved memory storage is provided for applying a raster scan search strategy for finding a reference image for the input video frame by applying a shift-based input addressing scheme to write to the memory storage and a corresponding shift-based output addressing scheme to read from the memory storage.

TECHNICAL FIELD

At least one of the present embodiments generally relates to a method or an apparatus for video encoding or decoding, and more particularly, to a method or an apparatus for efficiently providing video compression and/or decompression utilizing visual artifact smoothing or reduction between different video subsections encoded with different compression methods within a video frame, as well as an improved memory storage for motion estimation.

BACKGROUND

To achieve high compression efficiency, image and video coding schemes usually employ prediction, including motion vector prediction, and transform to leverage spatial and temporal redundancy in the video content. Generally, intra or inter prediction/coding/decoding is used to exploit the intra or inter frame correlation, then the differences between the original image and the predicted image, often denoted as prediction errors or prediction residuals, are transformed, quantized, and entropy coded. To reconstruct the video, the compressed data are decoded by inverse processes corresponding to the entropy coding, quantization, transformation, and prediction.

Digital content delivery space has gained significant importance and emphasis as the content sources move from a physical form into an electronic network transmission form. As the core wide area transmission networks, e.g. wide area networks (WAN), gain maturity and stability to support broad regions, edge networks, including the metropolitan networks (MAN), the last mile networks (such as, e.g., DSL, cable, mobile cell, and/or fixed point wireless networks) have taken revolutionary changes in technological approaches to deliver electronic content to an end user.

The consumer demand for information and content in real-time over the network cloud has not only increased, it has also broadened to cover the telephone and television services, which were traditionally delivered through dedicated independent national and edge networks. The converged network delivery vision is turning into reality.

Multimedia information in its native digital form is often too large for any reasonable network to deliver. Given the fact that the target recipient, the human, can tolerate lossy degradation of this class of content, compression has taken the role in resolving the multimedia delivery bottleneck. Almost all multimedia content are going through some form of compression. Major standards were developed to support this effort, including MPEG1, MPEG2, H.261, H.263, H.264, H.265, AVC, HEVC, ATSC, AVS, and etc.

Advances in compression continue to improve the compression effectiveness. As mentioned above, the current state of the art involves a tool box set of interdependent techniques to achieve final compression results. Within the tool box, there are two classes of methods that is of particular interest: intra encoding verses inter encoding. Typically, intra encoding predicts from information newly generated within the current frame to reconstruct the current frame, whereas, inter encoding leverages information of temporally different frames, including both future and past frames.

Motion estimation remains one of the most computationally demanding exercise within the compression tool kit. From the current image, it extracts a reference block of pixels, which it then uses to find the best match position in the reference image. To identify the best match, it seeks the smallest Sum-of-Absolute-Difference (SAD) value of all the possible positions in the reference image. There are many search algorithms to reduce the computational demand, including, e.g., hierarchical search, selected point search, dependent path search. The hierarchical search approach relies on image decimation to reduce the size of the image, which in turn reduces the total amount SAD calculations. Through a cascade of images at different scaled levels, the search will incrementally refine the search to incrementally high resolution. The selected point search computes the SAD through a limited set of pixel points within the block of pixels, instead of all the pixels within the block. The dependent path search leverages the SAD results of the local set of SAD results to determine the next set of pixel blocks to seek for the minimum SAD.

Gradient decent is commonly used as an algorithm to derive the direction of the next set of neighboring pixel blocks. Continuous raster-scan search, which also falls within the dependent path search category, interleaves the forward row scan and backward row scan so that each position is physically adjacent to the previous or next points.

For all three types of searches, the search sequence can have the following two types: neighbor or jump. The Jump sequence can select any next point to compute the SAD without any dependency of the previous point. This sequence introduces no additional loading to a cache-less sequential state machine, such as a computer or a CPU. But, when implemented in a pipeline architecture, in which the reference image pixels are pipelined through the search engine, jump based approach must clear the pipeline, resulting in loss of throughput efficiency. The neighbor sequence follows a locally bounded constraint, in which the next position must remain within a local vicinity from the current position. One type of implementation, the walking pattern search, would limit the next position to within the top, bottom, left, right, top left, top right, bottom left, bottom right positions.

SUMMARY

The drawbacks and disadvantages of the prior art are solved and addressed by one or more aspects described herein.

Therefore, according to an embodiment, a method performed by an apparatus is presented having one or more processors for encoding an input video frame into an output compressed video frame, wherein the input video frame comprising a plurality of surrounding neighboring video subsections surrounding a center video subsection, the method comprising: filtering the plurality of surrounding neighboring video subsections; compressing the filtered plurality of surrounding neighboring video subsections using a first compression method with an associated first compression parameter set; filtering the center video subsection; compressing the filtered center video subsection using the first compression method with the associated first compression parameter set; decompressing the compressed filtered center video subsection using a first decompression method corresponding to the first compression method; compressing again the decompressed filtered center video subsection using a second compression method; forming the output compressed video frame wherein the output compressed video frame comprising the plurality of compressed filtered surrounding neighboring video subsections surrounding the compressed again decompressed filtered center video subsection; applying a raster scan search strategy for finding a reference image for the input video frame by applying a shift-based input addressing scheme to write to a memory array and a corresponding shift-based output addressing scheme to read from the memory array.

According to another embodiment, an apparatus is presented for encoding an input video frame into an output compressed video frame, wherein the input video frame comprising a plurality of surrounding neighboring video subsections surrounding a center video subsection, the apparatus comprising: at least a memory; one or more processors configured to: filter the plurality of surrounding neighboring video subsections; compress the filtered plurality of surrounding neighboring video subsections using a first compression method with an associated first compression parameter set; filter the center video subsection; compress the filtered center video subsection using the first compression method with the associated first compression parameter set; decompress the compressed filtered center video subsection using a first decompression method corresponding to the first compression method; compress again the decompressed filtered center video subsection using a second compression method; form the output compressed video frame wherein the output compressed video frame comprising the plurality of compressed filtered surrounding neighboring video subsections surrounding the compressed again decompressed filtered center video subsection; apply a raster scan search strategy for finding a reference image for the input video frame by applying a shift-based input addressing scheme to write to the memory and a corresponding shift-based output addressing scheme to read from the memory.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an embodiment of a video encoder/encoding process within which aspects of the present embodiments may be implemented.

FIG. 2 illustrates another block diagram of an embodiment of a video encoder/encoding process within which aspects of the present embodiments may be implemented.

FIG. 3 illustrates switching of different compression methods according to aspects of the present embodiments.

FIG. 4 illustrates a video frame having different video subsections being encoding with different compression methods according to aspects of the present embodiments.

FIG. 5 illustrates another block diagram of an embodiment of a video encoder/encoding process within which aspects of the present embodiments may be implemented.

FIG. 6 illustrates a block diagram of an apparatus within which aspects of the present embodiments may be implemented.

FIG. 7 illustrates a process within which aspects of the present embodiments may be implemented.

FIG. 8 illustrates aspects of an improved memory storage for motion estimation.

FIG. 9 illustrates how an input pixel array may be located within a video frame.

FIG. 10 illustrates a vertical adjacency relationship between px1 single-dimensional pixel arrays.

FIG. 11 illustrates a horizontal adjacency relationship between px1 single-dimensional pixel arrays.

FIG. 12 illustrates exemplary components of a data storage module/memory/memories/memory array.

FIG. 13 illustrates an example of how a 3X3 pixel array is shifted and stored in distributed randomly accessible memories.

FIG. 14 illustrates an example of how various settings of 3X1 single-dimensional pixel array could be read from distributed randomly accessible memories which contain a shifted 3X3 pixel array.

FIG. 15 illustrates an example of how a 3x3 motion estimation window utilizes the distributed randomly accessible memories which contains a shifted 6X6 pixel array.

DETAILED DESCRIPTION

One aspect of the present embodiments relates to a recognition that the reconstruction method between the intra and inter encoding/decoding is fundamentally different, and therefore, the resulting distortion artifacts such as visual artifact between the two compression/decompression methods are also very different.

In addition, multimedia sequence reconstruction under transmission error conditions is critical to lossy transmission systems. Such systems may include wireless, congested wired network, and processing limited networks. An approach to rebuild the sequence after an error hit is to introduce intra encoding. Intra encoding can be introduced incrementally at local sections of a picture, or it can be introduced over the entire picture.

For low latency applications, the need for incremental progressive periodic video sequence refresh is a requirement. Full intra encoded frames are often too large, resulting in a longer compressed data delivery time, pushing out the overall video latency. For progressive refresh implementations, introduction of an artificial intra encoded area within the image (such as, e.g., in the center video frame position), and then progressively covering the entire area through subsequent images results in the reconstruction of the video sequence.

As mentioned previously, one aspect of the present embodiments relates to a recognition by the present inventor that the reconstruction method between the intra and inter encoding/decoding is fundamentally different, and therefore resulting in visual artifact distortion between the two different compression/decompression methods within a video sequence or a video frame.

Visual artifact is a visible artifact that looks like fragments of a checkerboard pattern, or single pixel pattern located in flat or low level textured areas around strong edges. For example, it is a visual distortion that appears near crisp edges of objects in video frames that are compressed with the discrete cosine transform (DCT). It typically occurs at decompression when the decoding engine has to approximate the discarded data by inverting the transform model. The visual artifact typically appears as random aliasing in these areas. As TVs get larger, visual artifact and other artifacts become more noticeable.

Accordingly, one aspect of the present embodiments provides visual artifact reduction processing/apparatus to reduce this art effect, particularly when blocks or subsections within a video frame are coded with different compression methods, such as, e.g., intra-coding or inter-coding. Therefore, present embodiments aim to reduce or smooth out the visual artifact within a video frame.

Accordingly, FIG. 4 shows one exemplary embodiment of a video frame 400 according an aspect of the present embodiments. Frame 400 is a video frame which is meant to be progressively refreshed. When updating a center subsection 409 using a compression method (e.g., intra encoding 410), those sub-sections 401-408 that have been compressed over the past by inter encoding methods 420 will result in a change in a distortion within the local region that may be visible by a human observer, even though that the overall distortion of the frame 400 remains the same as before and in future. A subsection may be a block, a subblock, or a macroblock, etc. of the video frame 400.

The same content region 400, when encoded at the same level of quantization, will still result in a visually detectable difference when encoded by an intra coding method 410 versus the inter-coding method 420.

Accordingly, present embodiments provide an inventive solution to smooth out or reduce the visual distortion differences across adjacent image subsections (e.g., across 408 and 409) having different compression methods (420, 410).

FIG. 5 illustrates an exemplary process and/or system 500 in which various aspects and embodiments are implemented. FIG. 5 shows a process and/or system 500 to reduce or smooth out the visual artifact contributed by the different compression methods of the subsections of the video frame 400. Accordingly, for example, given a video frame 400 with surrounding sub-sections 401-408 compressed by a primary encoding method (e.g., inter coding 420), and a center subsection 409 compressed by a secondary encoding method (e.g., intra coding 410), the visual artifact for center sub-section 409 compressed by the secondary method will be matched with the surrounding neighbor subsections 401-408 by an exemplary dual pass encoding process/system 500 shown in FIG. 5.

As illustrated in FIG. 5, video data 527 representing the center subsection 409 in FIG. 4 are pre-process filtered 530, compressed 535, and then de-compressed 540 with the primary compression engine/process (e.g., inter coding as in FIG. 4) using a common parameter set 515 used by all the neighbor subsections 401-408 in FIG. 4. In an additional or a second pass, the reconstructed video data outputted from de-compressing engine 540 are additionally compressed by another compression engine/process to compress the reconstructed video data using the secondary compression method that was used for the center sub-section 410 of video frame 400 in FIG. 4 (e.g., intra coding). The additionally compressed video data for this subsection 410 is then reconstructed or de-compressed 550. In one exemplary aspect, this second de-compression/reconstruction 550 is at a lower quantization setting than as it would have been set to normally. Accordingly, present embodiments effectively capturing the visual artifact generated by the primary compress method into the secondary compressing method, thereby smoothing out or reducing the distortion or the visual artifact across the two different compression methods.

Again, the encoding distortions including the visual artifact of an image subsection of a video frame 400 is largely dependent on the encoding method used, which is mainly contributed by the pre-process filter 510, the compress engine 520, and the parameter set 515 used for that encoder/encoding. Accordingly, the corresponding visual artifact is captured by four components in the process/apparatus of the FIG. 5: the input pre-processing filter 530, the compress engine 535, the parameter set 515 that configures the compress engine 535, and the de-compress engine 540 that reconstructs the input sub-section pixels with the same distortion. The distortion is effectively captured within the distorted pixels 543.

The compress engines/processes 520 530 545 may be of any type or class of compression methods, including but not limited to intra encoding, inter encoding, wavelet encoding, simple quantize methods, and etc. Within these encoding methods, pre-process filters 520 530 may include, but not limited to, noise reduction filters, low pass filters, motion compensation filters, or even transform domain filters.

Accordingly, present embodiments provide at least a method or an apparatus which will correlate visual artifacts from different compression methods within a video frame so that from a human perception perspective, the visual distortion across different compression methods is observed to be more uniform. The embodiments achieve this by capturing the noise distortion of a primary compression method in the secondary compression method. In doing so, the compressed sequence, when encoded with difference compression methods, will essentially have the noise of only the primary compression method.

FIG. 2 illustrates an exemplary system 200 in which various aspects and embodiments are implemented. During a normal operation, when there is no need for any visual artifact reduction or smoothing, the raw pixel data 210 are fed directly to either the Inter Compress Engine 260 or the Intra Compress Engine 270 through the Raw Pixel Switch 220. The Output Switch 295 will select accordingly the appropriate Compress Engine output to output an exemplary video frame 400 shown in FIG. 4.

As already described above, video frame 400 normally would comprise a center subsection 409 which is an area encoded using intra coding 410, and is surrounded by neighbor subsections 401-408 encoded using inter coding 420. But according to present embodiments, to smooth out the noise or distortion, for the encoding of the center subsection 409, the Raw Pixel Switch 220 will route the raw pixels 210 to the Inter Compress Engine 260 first (through Pre-process Filter 230) instead. The Inter Compress Engine 260 output is only used by the De-compress Engine 290. The Inter De-Compress Engine 290 output is then re-compressed by the Intra Compress Engine 270 via the Secondary Input Switch 240. In doing so, the distortion due to the first type of encoding is captured by the second type of encoding.

In an exemplary aspect of the present embodiments, a second encoding type may also be configured by the Parameter Set Manager 250 so that the additional distortion introduced by the second encoder is of a lower significance. Note that the first encoder has already removed a layer of information from the reconstructed data, thus, the second encoder will still offer good compression even though it is set to encode at a lower level of resolution. Only the output of the Intra De-compress Engine 270 output is delivered to the next stage of processing by the Output Switch 295.

The Parameter Set Manager 250 will deliver the appropriate parameter set (e.g., 515 shown in FIG. 5) to the Inter Compress Engine 260 and the Intra Compress Engine 270 at certain switching states (“switch”) as illustrated FIG. 3. That is, the switches 240 295 and the Parameter Set Manager 250 in FIG. 2 will change states only at the feed 310 and the process 330 boundary 320, shown in FIG. 3. The Compress Engines 260 and 270 in FIG. 2 receive data 320 and process the data 330 sequentially following a two phase process 300, as shown in FIG. 3.

As already mentioned above, the different types of compression/encoding includes, but not limited to, intra encoding, inter encoding, bi-directional encoding, DCT transform encoding, wavelet encoding, and other types of lossy or lossless encoding. In addition, the encoding size of the encoding methods could be as small as a sub pixel, to as large as multiple frames. Other possible encoding sizes may include, but not limited to, 1 macroblock (16x16 pixels), 1 row of macroblocks, one column of macroblocks, multiple columns for multiple rows of macroblocks, entire frame of macroblocks, multiple frames of pixels, or one slice of pixels.

Again, according to present embodiments, to minimize visual artifact, data sub-sections are classified into two categories: surrounding neighbor subsections 401 to 408, and a center sub-section 409. Each of these types of subsections follows a different processing flow, as illustrated in process/apparatus 500 in FIG. 5. The surrounding neighbor subsection data 505 follow a traditional process flow, going through first the pre-process filter 510 then a primary compress engine 520. The center subsection data 527 follows a dual pass encoding flow 530 535 540 545 550. The center subsection data 527 are first filtered by e.g., a pre-process filter 530 then encoded through a primary compress engine 535 using the same compression method as used by the primary compression engine 520 on the surrounding subsection data 505.

The compressed data from compress engine 535 are then de-compressed through a decompress engine 540, following a common parameter set 515. This common parameter set is used for both for the encoders in the neighbor subsections and the first encoding pass for the center sub-section. This primary compress engine is paired with decompress engine 540 which reconstructs the center subsection data 527 with distortion. This reconstructed distorted data are then re-encoded by the secondary compress engine 545, and decompress by the secondary decompress engine 550.

FIG. 1 illustrates an exemplary apparatus 100 in which various aspects and embodiments may be implemented. In this example, a H.264 AVC encoder is being modified according to the present embodiments to reduce or smooth out visual artifact. A camera 105 will capture video and output uncompressed data in pixel raster scan form with 422 chroma format. The output will contain both luma and chroma pixels following, e.g., the HDSDI standards SMPT292 and SMPTE274. The uncompressed data, for this example, is 1080i format. The format converter 110 will convert the 1080i format into 720p format uncompressed output following the SMPTE292M. The 422-420 converter 115 will reduce the chroma pixel count by half following the specification spelled out in MPEG2 video compression standard. The output of the 422-420 converter will send the raster scan luma and chroma pixel data to the MB generator 120.

The macroblock, “MB”, generator 120 will regroup the luma and chroma pixels in such a way so that it will output groups of 16x16 luma pixels, 8x8 Cb chroma pixels, and 8x8 Cr chroma pixels. The output macroblocks will have a relationship between each other such that they are located in raster scan locations as they come out of the MB generator. In other words, for a given video frame, the first MB will carry the Luma and chroma pixels with the top left 16x16 Luma pixel area. The second MB will carry the Luma and Chroma pixels starting at pixel 17 from the left corner of the picture, and pixel 1 from the top of the picture.

Under a normal condition, in which the encoding goal is to achieve best compression efficiency results, the on-going encoding configuration function 145 is turned on. In this case, the MB selector 125 will always route the MB generator 120 to the output. The intra predict engine 130 will predict the input MB using border pixel prediction, following, e.g., the H.264 AVC standard. The intra difference generator 150 will generate a difference output by subtracting the prediction output of the intra prediction engine 130 from the original pixels from the MB selector 125.

In parallel with the intra prediction engine 130 and the intra difference generator 150, the inter prediction engine 155 will predict the same set of pixels that the intra engines are working on. It will leverage the previous and future images in the sequence to predict the current set of MB pixels following the H.264 AVC standard. The inter difference generator 190 will then output the difference between the predicted data and the output date from the MB selector 125.

The on-going encode configuration algorithm 145 will then make a decision based on an algorithm. In one aspect according to the present embodiments, there is no constraints on the algorithm methodology. The Diff Select 135 will pass the difference pixels from either the intra diff engine 150 or the inter diff engine 190. The DCT engine 160 will carry out DCT transform following the H.264 AVC standard. The Quantizer 165 will carry out coefficient quantization following the H.264 AVC. The quantization level is set by the on-going encode configuration algorithm 145 to meet system objectives (e.g., band with constraint). The De-Quant engine 175 will carry out the inverse quantization following the H.264 AVC standard, using the same quantization level applied to the quantizer 165.

The inverse quantization engine 180 will carry out inverse DCT transform following the H.264 AVC standard. The output of the inverse quantizer 180 output is the reconstructed pixels. When the algorithm selector selects the on-going encode configuration algorithm 145, the reconstructed pixel output is then passed on to the deblock engine 194. The MB selector 125 will ignore the reconstructed pixels. The coefficients from the quantizer 185 are forwarded to the additional compression processing modules 140 to gain further compression gains, following the H.264 AVC when the on-going encode configuration algorithm 145 is selected.

The algorithm selector 196 can select the alternative Encoding Configuration Algorithm 170 for the purpose of introducing error recovery method, according to a visual artifact reduction process as described before and herein. Accordingly, the alternative algorithm will initiate the following procedures so to force an intra encoding on the currently selected pixel output from the MB selector 125.

The alternative encoding configuration algorithm 170 will allow the intra prediction engine 130, the intra diff engine 150, the inter prediction engine 155, and the inter diff engine 190 to process the pixels from the MB generator by appropriately configuring the MB selector 125. It will follow the on-going encode configuration algorithm 145 to control the Diff Select engine 135 to select between the intra and inter encoded data, and the quantization levels for the quantizer 165 and the de-quantizer 175. The DCT 160, Quant 165, De-Quant 175, and Inv Quant 180 engines will process the data to generate the reconstructed pixels. This set of reconstructed pixels will not pass through to the deblocker 194. It will be blocked by the reconstruct pixel output module. The Coefficients from Quant engine 165 is prevented from reaching the post processing (e.g., 140) by disabling the coefficient output 185.

The reconstructed pixel data from the Inv Quant engine 180 is fed back to the intra prediction 130 and Intra diff 150 engines by appropriately configuring the MB selector 125. The alternative encoding configuration algorithm 170 will configure the Diff selector 135 to only select the intra diff generator 150 output for this second pass. The DCT 160, Quant 165, De Quant 175, and the Inv Quant 180 engines will also carry out a second pass at processing the intra data.

In one exemplary non-limiting embodiment, the alternative encoding configuration algorithm 170 will configure the quantizer 165 and the de-quantizer 175 with a quantization level that is lower than the on-going encoding configuration algorithm 145 settings so to properly capture the first pass encoding distortion. The coefficient output is enabled by the alternative encoding configuration algorithm 170, allowing the post processing compression engine(s)/processes 140 to work on this set of coefficients. The deblock output 192 is also enabled to allow the second pass reconstructed pixels to pass into the de-blocker for processing.

FIG. 6 illustrates a block diagram of an example of a system in which various aspects and embodiments are implemented. System 1000 can be embodied as a device including the various components described below and is configured to perform one or more of the aspects described in this document. Examples of such devices, include, but are not limited to, various electronic devices such as personal computers, laptop computers, smartphones, tablet computers, digital multimedia set top boxes, digital television receivers, personal video recording systems, connected home appliances, and servers. Elements of system 1000, singly or in combination, can be embodied in a single integrated circuit (IC), multiple ICs, and/or discrete components. For example, in at least one embodiment, the processing and encoder/decoder elements of system 1000 are distributed across multiple ICs and/or discrete components. In various embodiments, the system 1000 is communicatively coupled to one or more other systems, or other electronic devices, via, for example, a communications bus or through dedicated input and/or output ports. In various embodiments, the system 1000 is configured to implement one or more of the aspects described in this document.

The system 1000 includes at least one processor 1010 configured to execute instructions loaded therein for implementing, for example, the various aspects described in this document. Processor 1010 can include embedded memory, input output interface, and various other circuitries as known in the art. The system 1000 includes at least one memory 1020 (e.g., a volatile memory device, and/or a non-volatile memory device). System 1000 includes a storage device 1040, which can include non-volatile memory and/or volatile memory, including, but not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash, magnetic disk drive, and/or optical disk drive. The storage device 1040 can include an internal storage device, an attached storage device (including detachable and non-detachable storage devices), and/or a network accessible storage device, as non-limiting examples.

System 1000 includes an encoder/decoder module 1030 configured, for example, to process data to provide an encoded video or decoded video, and the encoder/decoder module 1030 can include its own processor and memory. The encoder/decoder module 1030 represents module(s) that can be included in a device to perform the encoding and/or decoding functions. As is known, a device can include one or both of the encoding and decoding modules. Additionally, encoder/decoder module 1030 can be implemented as a separate element of system 1000 or can be incorporated within processor 1010 as a combination of hardware and software as known to those skilled in the art.

Program code to be loaded onto processor 1010 or encoder/decoder 1030 to perform the various aspects described in this document can be stored in storage device 1040 and subsequently loaded onto memory 1020 for execution by processor 1010. In accordance with various embodiments, one or more of processor 1010, memory 1020, storage device 1040, and encoder/decoder module 1030 can store one or more of various items during the performance of the processes described in this document. Such stored items can include, but are not limited to, the input video, the decoded video or portions of the decoded video, the bitstream, matrices, variables, and intermediate or final results from the processing of equations, formulas, operations, and operational logic.

In some embodiments, memory inside of the processor 1010 and/or the encoder/decoder module 1030 is used to store instructions and to provide working memory for processing that is needed during encoding or decoding. In other embodiments, however, a memory external to the processing device (for example, the processing device can be either the processor 1010 or the encoder/decoder module 1030) is used for one or more of these functions. The external memory can be the memory 1020 and/or the storage device 1040, for example, a dynamic volatile memory and/or a non-volatile flash memory. In several embodiments, an external non-volatile flash memory is used to store the operating system of, for example, a television. In at least one embodiment, a fast external dynamic volatile memory such as a RAM is used as working memory for video coding and decoding operations, such as for MPEG-2 (MPEG refers to the Moving Picture Experts Group, MPEG-2 is also referred to as ISO/IEC 13818, and 13818-1 is also known as H.222, and 13818-2 is also known as H.262), AVC, HEVC (HEVC refers to High Efficiency Video Coding, also known as H.265 and MPEG-H Part 2), or VVC (Versatile Video Coding, a new standard being developed by WET, the Joint Video Experts Team).

The input to the elements of system 1000 can be provided through various input devices as indicated in block 1130. Such input devices include, but are not limited to, (i) a radio frequency (RF) portion that receives an RF signal transmitted, for example, over the air by a broadcaster, (ii) a Component (COMP) input terminal (or a set of COMP input terminals), (iii) a Universal Serial Bus (USB) input terminal, and/or (iv) a High Definition Multimedia Interface (HDMI) input terminal. Other examples, not shown in FIG. 10, include composite video.

In various embodiments, the input devices of block 1130 have associated respective input processing elements as known in the art. For example, the RF portion can be associated with elements suitable for (i) selecting a desired frequency (also referred to as selecting a signal, or band-limiting a signal to a band of frequencies), (ii) downconverting the selected signal, (iii) band-limiting again to a narrower band of frequencies to select (for example) a signal frequency band which can be referred to as a channel in certain embodiments, (iv) demodulating the downconverted and band-limited signal, (v) performing error correction, and (vi) demultiplexing to select the desired stream of data packets. The RF portion of various embodiments includes one or more elements to perform these functions, for example, frequency selectors, signal selectors, band-limiters, channel selectors, filters, downconverters, demodulators, error correctors, and demultiplexers. The RF portion can include a tuner that performs various of these functions, including, for example, downconverting the received signal to a lower frequency (for example, an intermediate frequency or a near-baseband frequency) or to baseband. In one set-top box embodiment, the RF portion and its associated input processing element receives an RF signal transmitted over a wired (for example, cable) medium, and performs frequency selection by filtering, downconverting, and filtering again to a desired frequency band. Various embodiments rearrange the order of the above-described (and other) elements, remove some of these elements, and/or add other elements performing similar or different functions. Adding elements can include inserting elements in between existing elements, such as, for example, inserting amplifiers and an analog-to-digital converter. In various embodiments, the RF portion includes an antenna.

Additionally, the USB and/or HDMI terminals can include respective interface processors for connecting system 1000 to other electronic devices across USB and/or HDMI connections. It is to be understood that various aspects of input processing, for example, Reed-Solomon error correction, can be implemented, for example, within a separate input processing IC or within processor 1010 as necessary. Similarly, aspects of USB or HDMI interface processing can be implemented within separate interface ICs or within processor 1010 as necessary. The demodulated, error corrected, and demultiplexed stream is provided to various processing elements, including, for example, processor 1010, and encoder/decoder 1030 operating in combination with the memory and storage elements to process the datastream as necessary for presentation on an output device.

Various elements of system 1000 can be provided within an integrated housing, within the integrated housing, the various elements can be interconnected and transmit data therebetween using suitable connection arrangement, for example, an internal bus as known in the art, including the Inter-IC (I2C) bus, wiring, and printed circuit boards.

The system 1000 includes communication interface 1050 that enables communication with other devices via communication channel 1060. The communication interface 1050 can include, but is not limited to, a transceiver configured to transmit and to receive data over communication channel 1060. The communication interface 1050 can include, but is not limited to, a modem or network card and the communication channel 1060 can be implemented, for example, within a wired and/or a wireless medium.

Data is streamed, or otherwise provided, to the system 1000, in various embodiments, using a wireless network such as a Wi-Fi network, for example IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers). The Wi-Fi signal of these embodiments is received over the communications channel 1060 and the communications interface 1050 which are adapted for Wi-Fi communications. The communications channel 1060 of these embodiments is typically connected to an access point or router that provides access to external networks including the Internet for allowing streaming applications and other over-the-top communications. Other embodiments provide streamed data to the system 1000 using a set-top box that delivers the data over the HDMI connection of the input block 1130. Still other embodiments provide streamed data to the system 1000 using the RF connection of the input block 1130. As indicated above, various embodiments provide data in a non-streaming manner. Additionally, various embodiments use wireless networks other than Wi-Fi, for example a cellular network or a Bluetooth network.

The system 1000 can provide an output signal to various output devices, including a display 1100, speakers 1110, and other peripheral devices 1120. The display 1100 of various embodiments includes one or more of, for example, a touchscreen display, an organic light-emitting diode (OLED) display, a curved display, and/or a foldable display. The display 1100 can be for a television, a tablet, a laptop, a cell phone (mobile phone), or other devices. The display 1100 can also be integrated with other components (for example, as in a smart phone), or separate (for example, an external monitor for a laptop). The other peripheral devices 1120 include, in various examples of embodiments, one or more of a stand-alone digital video disc (or digital versatile disc) (DVR, for both terms), a disk player, a stereo system, and/or a lighting system. Various embodiments use one or more peripheral devices 1120 that provide a function based on the output of the system 1000. For example, a disk player performs the function of playing the output of the system 1000.

In various embodiments, control signals are communicated between the system 1000 and the display 1100, speakers 1110, or other peripheral devices 1120 using signaling such as AV.Link, Consumer Electronics Control (CEC), or other communications protocols that enable device-to-device control with or without user intervention. The output devices can be communicatively coupled to system 1000 via dedicated connections through respective interfaces 1070, 1080, and 1090. Alternatively, the output devices can be connected to system 1000 using the communications channel 1060 via the communications interface 1050. The display 1100 and speakers 1110 can be integrated in a single unit with the other components of system 1000 in an electronic device such as, for example, a television. In various embodiments, the display interface 1070 includes a display driver, such as, for example, a timing controller (T Con) chip.

The display 1100 and speaker 1110 can alternatively be separate from one or more of the other components, for example, if the RF portion of input 1130 is part of a separate set-top box. In various embodiments in which the display 1100 and speakers 1110 are external components, the output signal can be provided via dedicated output connections, including, for example, HDMI ports, USB ports, or COMP outputs.

The embodiments can be carried out by computer software implemented by the processor 1010 or by hardware, or by a combination of hardware and software. As a non-limiting example, the embodiments can be implemented by one or more integrated circuits. The memory 1020 can be of any type appropriate to the technical environment and can be implemented using any appropriate data storage technology, such as optical memory devices, magnetic memory devices, semiconductor-based memory devices, fixed memory, and removable memory, as non-limiting examples. The processor 1010 can be of any type appropriate to the technical environment, and can encompass one or more of microprocessors, general purpose computers, special purpose computers, and processors based on a multi-core architecture, as non-limiting examples.

FIG. 7 illustrates an exemplary process/algorithm 700 for implementing aspects of present exemplary embodiments. At 701, process/algorithm 700 a plurality of surrounding neighboring video subsections of a video frame. At 702, process/algorithm 700 compresses the filtered plurality of surrounding neighboring video subsections using a first compression method with an associated first compression parameter set. At 703, process/algorithm 700 filters the center video subsection. At 704, process/algorithm 700 compresses the filtered center video subsection using the first compression method with the associated first compression parameter set. At 705, process/algorithm 700 decompresses the compressed filtered center video subsection using a first decompression method corresponding to the first compression method. At 706, process/algorithm 700 compresses again the decompressed filtered center video subsection using a second compression method. At 707, process/algorithm 700 forms the output compressed video frame wherein the output compressed video frame comprising the plurality of compressed filtered surrounding neighboring video subsections surrounding the compressed again decompressed filtered center video subsection.

In one aspect of the present embodiments, the visual artifact reduced, doubly compressed video frame is able to be decoded by a standard compliant decoder such as one illustrated in FIG. 6. That is, for example, a video frame which is doubly compressed via blocks 530-550 in FIG. 5, using e.g., a HEVC compliant primary, inter-coding method and then a HEVC complaint secondary, intra-coding method, is still HEVC compliant. Therefore, according to one aspect of the present embodiments, in the above example, any HEVC complaint decoder will be able to decode the doubly compressed output video frame with no modifications.

Another aspects of the present embodiments improve the hierarchical search, selected point search, and/or the dependent path search motion estimation that uses a neighbor walking pattern search strategy by leveraging either or both the distributed random accessible memories and/or a shift-based data relocation method that is applied to pixel elements stored at distributed random accessible memory locations of a memory, memories or a memory array. The proposed solution removes sequential reads on the memory/memories/memory array to achieve higher computation throughput.

As already mentioned previously, there are multiple motion estimation solutions available, both in the industry and in the academic space. The raster scan strategy searches for blocks in a reference frame to predict the current block with minimal rate-distortion. It is typically the most computationally intensive function and an efficient implementation is highly desirable. The number of memory accesses is a critical factor in an efficient implementation.

With a raster scan strategy, the motion estimation windows sweep horizontally left-to-right at a steady rate. The conventional method of implementing a raster scan strategy has to move back to the left once it finishes scanning a line. Such an implementation may discard data that have already been extracted from the image and result in extra memory accesses. To fully reuse the data, the motion estimation windows must be able to sweep: (a) horizontally left-to-right, (b) horizontally right-to-left, (c) vertically top-to-bottom, and (d) vertically bottom-to-top. For clarity, this scan method is termed a “continuous raster-scan.” However, in storing the pixel rows or the pixel columns of images to fixed random accessible memories, the motion estimation with the raster scan strategy has to perform sequential reads when the whole pixel row or the whole pixel column all come from one physical memory. Such a sequential read behavior increases the number of memory accesses and reduces computation throughput.

Accordingly, motion estimation often requires reading pixel elements sequentially from memory/memories for further processing. In doing so, it introduces performance bottleneck caused by sequential reads of the memory/memories when following, e.g., the walk sequence algorithm. Therefore, the present embodiments create an apparatus and/or a method to parallelize memory reads through data relocation, so that a row or a column of each block can be read on a single cycle, regardless of the direction of the next read point. The present embodiments thus provide an architecture to compute memory addresses required by data relocation so that there is no sequential reads of the memory/memories during motion estimation.

Again, in the prior implementations, motion estimation using raster scan search strategy will have to spend extra clock cycles on sequential reads of the memory/memories, even with distributed memory/memories. The proposed modifications according to present embodiments provide an improved way as to how a pixel element is stored inside distributed random accessible memories. It will result in completely parallel reads on memories, thus will remove the performance bottleneck and achieve one estimation per window per cycle to achieve great speed/efficiency.

FIG. 8 shows one exemplary embodiment 800 consists of three modules: a data pre-processing module 801, a distributed memory module 802, and a processing module 803. According to an embodiment, the data pre-processing module 801 captures each image of a video sequence, and carry out the following processing:

-   -   It will segment the image into a fixed number of         single-dimensional pixel arrays (e.g., p, 904) for a video frame         900, as shown in FIG. 9.     -   It will take each single-dimensional pixel array and write it         into the distributed memory module 802.     -   It will further compute the memory address for each pixel         element in the single-dimensional pixel array (e.g., through a         shifting calculation). The memory address is then utilized when         writing the pixel element in to the memory module 802.

For each pixel element in the single-dimensional pixel array, there will be one unique memory for data storage. A typical size of the single-dimensional pixel array would be 16x1. Therefore, there will be 16 different distributed memories/memory locations existing in the distributed memory module. Each memory in the distributed memory module has at least four ports: read data, read address, write data and write address. The width of read data port and write data port is identical to the width of the pixel element. A typical width of the pixel element would be 8 bits.

FIG. 10 illustrates the vertical adjacency relationship between different px1 single-dimensional pixel arrays (e.g., 1000 vs. 1002). FIG. 11 illustrates the horizontal adjacency relationship between different px1 single-dimensional pixel arrays (e.g., 1104 vs. 1102). FIG. 12 illustrates another example of data storage memory module 1200 comprising a plurality of memories or memory locations RAM-1 to RAM-p for implementing the present embodiments.

As shown in FIG. 13, the memory addresses of all pixel elements in the single-dimensional pixel array are equivalent. For example, pixel element (0,0), (0,1) and (0,2) are all written to address 0 of RAM-1, RAM-2 and RAM-3 respectively. It is the order of memory to be stored that is computed on-the-fly. For example, pixel element (1,0) is no longer written to RAM-1, as its predecessor does, but to RAM-2. A typical implementation of this strategy is by utilizing a shifter which cyclically shifts the pixel elements in the single-dimensional pixel array before they are written to the memory. The shift amount is typically the absolute vertical position of a single-dimensional pixel array in the original image.

On the read side of the distributed memories, when extracting the pixel elements for motion estimation, it requires calculating the read address for each pixel element in the single-dimensional pixel array. The addresses for pixel elements need not be the same. Therefore, the distributed memories can provide the processing module 803 both column-consecutive pixel array and row- consecutive pixel array. As an example, for an instance shown in FIG. 14, a 3x3 pixel array stored in a distributed memory module can output 3x1 pixel arrays following either (0,0), (0,1), (0,2) order or (0,0), (1,0), (2,0) order. Both orders are utilized by the raster scan strategy when moving the motion estimation window by various directions.

FIG. 15 shows two 3x3 motion estimation window examples during a motion estimation process on a 6x6 image. The top window could move three pixels towards bottom then one pixel to right to reach the bottom window.

Accordingly, present embodiments provide an exemplary data pre-processing module (e.g., 801 in FIG. 8), which takes in a pixel array from consecutive sequence of images, and assigns pixels to groups of distributed memories (e.g., 802 in FIG. 8; 1200 in FIG. 12; 1301 in FIG. 13) with computed memory addresses, which stores a subset region of images, and a data processing module (e.g., 803 of FIG. 8), which retrieves and analyzes only a finite number of sequentially captured sub-areas. In one exemplary embodiment, a two-dimensional pixel array of mxn (m horizontal pixels and n vertical pixels) is segmented into a set of single-dimensional pixel array of px1 (p horizontal pixels and 1 vertical pixels).

In another embodiment, the px1 single-dimensional pixel arrays have a sequential relationship where the previous fetched px1 single-dimensional pixel array is adjacent to the border of current px1 single-dimensional pixel array. In another embodiment, the width of two-dimensional pixel array of m is an integer times of the width of single-dimensional pixel array p.

Accordingly, aspects of the present embodiments improve the block-based motion estimation using a raster scan search strategy by applying a shift-based input addressing scheme and a corresponding shift-based output addressing scheme to the distributed random accessible memory/memories/memory array. The implementation achieves a block column read on every clock cycle throughout the raster scan process, achieving higher computation throughput.

In other aspects, the raster scan search strategy for finding the reference image for the input video frame may comprise using a data pre-processing module, segmenting the input video frame into a fixed number of single-dimensional pixel arrays, computing a corresponding write memory address for each pixel element of the fixed number of the single-dimensional pixel arrays via an input shift calculation of the shift-based input addressing scheme, and writing the each element of the fixed number of the single-dimensional pixel array into the memory array using the calculated shifted write memory address.

In addition, in other aspects, the raster scan search strategy for finding the reference image for the input video frame may further comprise using a data processing module, computing a corresponding read memory address for the each pixel element of the fixed number of the single-dimensional pixel arrays via an output shift calculation of the shift-based output addressing scheme, and reading the each element of the fixed number of the single-dimensional pixel array from the memory array using the calculated shifted read memory address.

Various implementations involve decoding. “Decoding”, as used in this application, can encompass all or part of the processes performed, for example, on a received encoded sequence in order to produce a final output suitable for display. In various embodiments, such processes include one or more of the processes typically performed by a decoder, for example, entropy decoding, inverse quantization, inverse transformation, and differential decoding. In various embodiments, such processes also, or alternatively, include processes performed by a decoder of various implementations described in this application.

As further examples, in one embodiment “decoding” refers only to entropy decoding, in another embodiment “decoding” refers only to differential decoding, and in another embodiment “decoding” refers to a combination of entropy decoding and differential decoding. Whether the phrase “decoding process” is intended to refer specifically to a subset of operations or generally to the broader decoding process will be clear based on the context of the specific descriptions and is believed to be well understood by those skilled in the art.

Various implementations involve encoding. In an analogous way to the above discussion about “decoding”, “encoding” as used in this application can encompass all or part of the processes performed, for example, on an input video sequence in order to produce an encoded bitstream. In various embodiments, such processes include one or more of the processes typically performed by an encoder, for example, partitioning, differential encoding, transformation, quantization, and entropy encoding. In various embodiments, such processes also, or alternatively, include processes performed by an encoder of various implementations described in this application.

As further examples, in one embodiment “encoding” refers only to entropy encoding, in another embodiment “encoding” refers only to differential encoding, and in another embodiment “encoding” refers to a combination of differential encoding and entropy encoding. Whether the phrase “encoding process” is intended to refer specifically to a subset of operations or generally to the broader encoding process will be clear based on the context of the specific descriptions and is believed to be well understood by those skilled in the art.

Note that the syntax elements as used herein, are descriptive terms. As such, they do not preclude the use of other syntax element names.

When a figure is presented as a flow diagram, it should be understood that it also provides a block diagram of a corresponding apparatus. Similarly, when a figure is presented as a block diagram, it should be understood that it also provides a flow diagram of a corresponding method/process.

The implementations and aspects described herein can be implemented in, for example, a method or a process, an apparatus, a software program, a data stream, or a signal. Even if only discussed in the context of a single form of implementation (for example, discussed only as a method), the implementation of features discussed can also be implemented in other forms (for example, an apparatus or program). An apparatus can be implemented in, for example, appropriate hardware, software, and firmware. The methods can be implemented in, for example, a processor which refers to processing devices in general, including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as, for example, computers, cell phones, portable/personal digital assistants (“PDAs”), and other devices that facilitate communication of information between end-users.

Reference to “one embodiment” or “an embodiment” or “one implementation” or “an implementation”, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment” or “in one implementation” or “in an implementation”, as well any other variations, appearing in various places throughout this application are not necessarily all referring to the same embodiment.

Additionally, this application may refer to “determining” various pieces of information. Determining the information can include one or more of, for example, estimating the information, calculating the information, predicting the information, or retrieving the information from memory.

Further, this application may refer to “accessing” various pieces of information. Accessing the information can include one or more of, for example, receiving the information, retrieving the information (for example, from memory), storing the information, moving the information, copying the information, calculating the information, determining the information, predicting the information, or estimating the information.

Additionally, this application may refer to “receiving” various pieces of information. Receiving is, as with “accessing”, intended to be a broad term. Receiving the information can include one or more of, for example, accessing the information, or retrieving the information (for example, from memory). Further, “receiving” is typically involved, in one way or another, during operations such as, for example, storing the information, processing the information, transmitting the information, moving the information, copying the information, erasing the information, calculating the information, determining the information, predicting the information, or estimating the information.

It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as is clear to one of ordinary skill in this and related arts, for as many items as are listed.

Also, as used herein, the word “signal” refers to, among other things, indicating something to a corresponding decoder. For example, in certain embodiments the encoder signals a particular one of intra modes, or reference lines for intra prediction. In this way, in an embodiment the same parameter is used at both the encoder side and the decoder side. Thus, for example, an encoder can transmit (explicit signaling) a particular parameter to the decoder so that the decoder can use the same particular parameter. Conversely, if the decoder already has the particular parameter as well as others, then signaling can be used without transmitting (implicit signaling) to simply allow the decoder to know and select the particular parameter. By avoiding transmission of any actual functions, a bit savings is realized in various embodiments. It is to be appreciated that signaling can be accomplished in a variety of ways. For example, one or more syntax elements, flags, and so forth are used to signal information to a corresponding decoder in various embodiments. While the preceding relates to the verb form of the word “signal”, the word “signal” can also be used herein as a noun.

As will be evident to one of ordinary skill in the art, implementations can produce a variety of signals formatted to carry information that can be, for example, stored or transmitted. The information can include, for example, instructions for performing a method, or data produced by one of the described implementations. For example, a signal can be formatted to carry the bitstream of a described embodiment. Such a signal can be formatted, for example, as an electromagnetic wave (for example, using a radio frequency portion of spectrum) or as a baseband signal. The formatting can include, for example, encoding a data stream and modulating a carrier with the encoded data stream. The information that the signal carries can be, for example, analog or digital information. The signal can be transmitted over a variety of different wired or wireless links, as is known. The signal can be stored on a processor-readable medium.

We describe a number of embodiments. Features of these embodiments can be provided alone or in any combination. 

The invention claimed is:
 1. A computer program product for encoding an input video frame into an output compressed video frame, wherein the input video frame comprising a plurality of surrounding neighboring video subsections surrounding a center video subsection, the computer program product comprising computing instructions stored on a non-transitory computer storage medium and when the computing instructions are executed by one or more processor, configure the one or more processor to: filter the plurality of surrounding neighboring video subsections; compress the filtered plurality of surrounding neighboring video subsections using a first compression method with an associated first compression parameter set; filtering the center video subsection; compress the filtered center video subsection using the first compression method with the associated first compression parameter set; decompress the compressed filtered center video subsection using a first decompression method corresponding to the first compression method; compress again the decompressed filtered center video subsection using a second compression method; form the output compressed video frame wherein the output compressed video frame comprising the plurality of compressed filtered surrounding neighboring video subsections surrounding the compressed again decompressed filtered center video subsection; and apply a raster scan search strategy for finding a reference image for the input video frame by applying a shift-based input addressing scheme to write to a memory array and a corresponding shift-based output addressing scheme to read from the memory array.
 2. The computer program product of claim 1 wherein the applying the raster scan search strategy for finding the reference image for the input video frame further comprising: using a data pre-processing module, segmenting the input video frame into a fixed number of single-dimensional pixel arrays, computing a corresponding write memory address for each pixel element of the fixed number of the single-dimensional pixel arrays via an input shift calculation of the shift-based input addressing scheme, and writing the each element of the fixed number of the single-dimensional pixel array into the memory array using the calculated shifted write memory address.
 3. The computer program product of claim 2 wherein the applying the raster scan search strategy for finding the reference image for the input video frame further comprising: using a data processing module, computing a corresponding read memory address for the each pixel element of the fixed number of the single-dimensional pixel arrays via an output shift calculation of the shift-based output addressing scheme, and reading the each element of the fixed number of the single-dimensional pixel array from the memory array using the calculated shifted read memory address.
 4. The computer program product of claim 3 further comprising quantizing using a first quantizing resolution to compress the filtered plurality of surrounding neighboring video subsections.
 5. The computer program product of claim 4 further comprising quantizing using a quantizing resolution which is lower than the first quantizing resolution to compress again the decompressed compressed filtered center video subsection. 